Unease within the defense community over Caspar Weinberger has blossomed into panic now that the defense secretary-designate has booted out "Reaganaut" military advisers, trashed their recommendations and at least opened the door for soft-liners.

The certain appointment of Frank Carlucci, the Carter administration's deputy CIA director, as deputy secretary of defense is the visible tip of concealed events. In a Dec. 20 shouting match, Cap the Knife fired defense expert William Van Cleave as transition chief, black-balled him and his team from Pentagon posts and consigned their reports to ash cans. Since then, a collection of onsigned their reports to ash cans. Since then, a collection of personalities never connected with strong defense has been edging into the Reagan transition.

The most charitable explanation is that this is no conspiracy but the product of Weinberger's nearly total ignorance on defense questions, which was fully revealed in his Senate confirmation hearing. But asuming Weinberger finally learns the names and issues involved, he has lost valuable time in revising defense spending and lost invaluable experts he badly needs.

In this as in other transition wars these past two months, Ronald Reagan's presence is barely felt. There has been no gesture from either the president-elect or his chief aide, Ed Meese, that they regard a radical reconstruction of the nation's depleted defenses as top priority.

Consider the Reagan-Meese view toward Weinberger's insistence on Carlucci, a civil servant with no Defense Department background, as deputy secretary. Reagan's "kitchen cabinet" unanimously recommended against it, as did his defense transition team. The president-elect might then have suggested saving the deputy secretary's spot for an expert. Instead, Reagan acquiesced.

That was the situation when Van Cleave, Reagan's defense adviser throughout the campaign, went to California Dec. 20 to brief Weinberger. The secretary-designate was in an ugly mood. He unjustly believed Van Cleave was responsible for a press campaign against Carlucci.

An icy Weinberger informed Van Cleave that he and his team's services were terminated forthwith. The hot-tempered Van Cleave shouted that his responsibility was to advise Reagan himself and Weinberger could not fire him. Weinberger shouted back that Van Cleave was deceiving himself; he was gone.

Weinberger was correct. Early in the transition period when Van Cleave crossed swords with transition overseer William Timmons, a Timmons aide asked Meese whether Van Cleave was under the president-elect's protection. No, replied Meese, fire him if you want. The trouble blew over temporarily, but Reagan has not come to his defense adviser's aid.

Van Cleave was not the only victim. His team's members, including some of the nation's leading military experts, are blackballed. That includes the highly esteemed Ben Plymale of Boeing, who made the disastroud Dec. 20 trip west with Van Cleave. Plymale had been expected to be an adornment of the Reagan Pentagon as undersecreatry for research.

The defense plans fastidiously prepared by Van Cleave, Plymale and associates will never be read by Weinberger. That may well prevent any Reagan hurry-up plans for accelerated spending in the current fiscal year.

Pentagon offices formerly occupied by the Van Cleave team are now mostly empty. In charge of the skeleton crew there is an old Weinberger-Carlucci comrade from HEW days in the Nixon administration: William Howard Taft III, a Washington lawyer who knows even less about defense than Weinberger and Carlucci. Yet, incredibly, Taft has wound up on the list for the department's No. 3 post: undersecretary for policy.

Taft has been conferring on defense matters with Richard Stubbing, a Carter administration anti-defense expert at the Office of Management and Budget whose views generally coincide with Sen. George McGovern's. With Reaganauts exiled to oblivion, among those briefing Weinberger for his confirmation hearing were two Carter officials: Jack Stempler, assistant defense secretary for legislative affairs, and Brig. Gen. Carl Smith, military assistant to Defense Secretary Harold Brown.

Carlucci has been consulting with his close friend (another HEW old hand), John Rhinelander -- who was a passionate arms-controller as a State Department lawyer. Carlucci told us Rhinelander will not go into the Reagan administration and denied he even knows Barry Blechman, a former Carter administration arms-controller now at the Carnegie Endowment. But a memo circulating on Capitol Hill lists Blechman as a possible assistant secretary of defense.

There are antidotes. Secretary-designate Alexander Haig has moved quickly to install a Reaganaut staff at the State Department. The National Security Council staff will be filled with Reaganauts, possibly including Van Cleave. Despite his less-than-reassuring confirmation testimony, Weinberger may soon learn enough to reflect Reagan's philosophy in personnel and policy. But for now, one Senate conservative is calling Weinberger "another Harold Brown with one difference -- Brown knows something about defense."